Adjusting device for pump impellers



Dec. 23, 1958 H. HORNSCHUCH ETAL 2,865,299

ADJUSTING DEVICE FOR PUMP IMPELLERS Filed June 14, 1954 mm 2. mm T||| mm mm 6 mm pm W E E INVENTORS HANNS HORNSCHUCH ALEXANDER BRKICH THEIR ATTORNEY United States ADJUSTING DEVllCE FOR PUMP IIVIPELLERS' Application June 14, 1954, Serial. No. 436,340

6 Claims. (Cl. 103-411) This invention relates to pumps, and more particularly to centrifugal pumps serving to pump water carrying abrasive material, such as mud, sand and the like.

In pumps intended for service of the type described, the abrasive material entrained in the water effects rapid wear upon the portions of the pump which define the clearances between its rotative and the stationary parts, and in many structures, when the parts serving to prevent back-flow from the discharge channels to-the inlet side of the impellers become worn tothe extent of seriously lowering the .efficiencyof the pump it becomes necessary to disassemble the pump in order to restore it to its original condition.

It is accordingly an object of the present invention to render the impellers readily adjustable axially of the pumping chambers to assure the correct clearances between the impellers and the pump casing.

Another object is to enable such adjustment of the impellers to be made without requiring thedisassembling of the pumping mechanism.

A more specific object is to make possible theradjustment of the impellers axially of the pumping chambers from the exterior of the pump.

Still anotherobject is to enable such" adjustment ofithe pump impellers to be effected without disturbing the bearings for the pump shafting or the sealing devices serving to prevent leakage of fiuid'from the pumping chambers to the bearings.

Other objects will be in part obvious and in part pointed out hereinafter.

Inthe drawings accompanying this specificationand in whichsimilar reference numerals referto similar parts,

Figure l is a longitudinalview, partly broken away, of a multi-stage pump equipped with an adjusting device constructed in accordance with the practice of the invention,

Fig. 2 is a similar view somewhat enlargedof a fragmentary portion of the pump showing more particularly the wearing plates on the impellers and'the' pump casing depended upon to maintain the correct degrees of clearances between the impellers and thepumpfcasing,

Fig. 3 is a transverse. view taken through Figure'l on the line 3-3 looking in the direction indicated-by the arrows, and

Fig. 4 is an enlarged view, partly in section, of the adjusting device for the impeller shaft.

Referring more particularly to the drawings, 20. designates,- in general, a cen'trifugalpump comprising acasing 21, an impeller assembly 22, a shaft'assembly24 for the impeller assembly and a drive shaft 25 for transmitting rotary movement to the shaft assembly. 24 from. a motor (not shown).

The casing 21 is recessed to provide a chamber 26. for the accommodation of an inner casing 27 which is held against endwise movement by a wall 28 at the inner end of the chamber 26 and by a head 29 which. forms a closure for the chamber 26 and is secured to the casing 21 by bolts 30. The inner casing 27 is retained in axial alignatent O ice 2 ment with the shaft assembly 24 by annular flanges 31 and 32 at its forward and rearward ends that are in telescopic engagement with the head 29 and the casing 21, respectively, and a pin 33 seated in the casing 21 interlock-ingly engages the inner casing 27 to prevent rotation thereof within the chamber 26.

The inner casing has a loose fit within the chamber 26 so that it may be readily removed, if required, and is recessed to provide a pair of chambers 34 and 35 for the accommodation of impellers 36 and 37, respectively. The impeller 36 constitutes the initial stage of the pump and water is conveyed to its eye 38 by an inlet passage 39 in the head 29. The water discharged by the impeller 36 passes therefrom to the impeller 37 through a channel 40 in the inner casing 27 and a passageway 41 in the inner casing conveys the fluid discharged by the impeller 37 to a discharge passage 42 in the casing 21.

In accordance with the practice of the invention, the shaft assembly 24 comprises a hollow shaft 43 and an impeller shaft 44 which is disposed within the shaft 43 and connected to the impellers 36 and 37. The end portion 45 of the shaft 44 lying within the inner casing 27 is of somewhat smaller diameter than the body of the shaft and at the juncture of the reduced portion 45 and such body is a shoulder 46 that abuts an introverted flange 47 in the hub of the impeller 37 which is drivingly connected to the shaft 44 by akey 48. The impeller 36 is mounted only on the reduced portion 45 of the shaft 44. It has a threaded connection 49 therewith and bears against the hub of the impeller 37 to press the flange 4'7 against the shoulder 46.

The impellers are provided with flat Wearing plates 50 of annular shape that seat against the ends of the impellers to encircle the eyes thereof and cooperate with similar wearing plates 51 in the opposed surfaces of the casing parts to define clearances 52 between the inlet sides of the impellers and the casing. The wearing plates 50 and 51 lie normal to the shaft 44 and may be secured in position in any well known manner as .by seating the plates 51 in the casings and by providing the Wearing plates 50 with flanges 53 to seat in annular grooves 54 in the peripheries of the inlet end portions of the impellers. The widths of the clearances 52 are somewhat exaggerated in Fig. 2 of the drawings and it is to be understood that they are no greater than is required to avoid contact between the wearing plates 5% and 51 in order to minimize leakage of fluid from the impeller chambers through the clearances 52 to the inlet sides of the impellers.

The impeller shaft 44 has a sliding fit within the hollow shaft 43 and the latter is journaled inbearings 55 and 56 which are located, respectively, near the cham ber 26' and adjacent the outer end of the casing 21. The shaft' 43 carries a thrust bearing 57 and is provided with a suitable mechanical sealing device 58 at its innermost end to prevent leakage of fluid from the impeller chambers and associated channels along the exterior of the shaft 43.

In accordance with the invention, the shaft 4'4 is of greater length than the hollow shaft and anend portion 59 projects from the hollow shaft 43 and has a thread e'd terminal portion 6llfor the accommodation of a nut 61 whereby the shaft 44 may be movedaxially of the shaft 43. The nut 61 is interposed between coupling members 62 and 63 mounted upon the shafts 44 and 25, respectively, and the coupling members are drivingly connected to the shafts by keys 64, the'keyway 65 in the shaft 44 being ofsuflicient length to permit of adjustment of the shaft 44 without hindrance by its-key 64;

The coupling member'62 is secured to the hollow shaft 43- by bolts 66, and bolts 67 extending through the vnut with respect to the shaft 44-.

coupling members and the nut clamp these parts securely together and also prevent unauthorized rotation of the The shafts 25 and 44 are held in axial alignment with each other by bosses es and 69 on the coupling member s3 and the nut 61 which are seated in depressions 7d and 71 in the nut fill and the coupling member 62, respectively.

Preferably, a guard 72, of cup-shape, is disposed about i the coupling assembly and the nut 61 and secured to the end of the casing 21 by bolts 73.

in practice, whenever it becomes apparent that the etliciency of the pump has been lowered as a consequence of erosion on the plates 5t and 51, the impellers may be adjusted axially of the impeller chambers to restore the clearances 52 to their original widths in the following manner. First, the guard 72 is removed from the casing 21 to uncover the coupling assembly. The bolts all are then removed to release the nut er and the nut is rotated to effect movement of the shaft 44 in a right hand direction, as'Figure l is viewed in the drawings, until the wearing plates 50 engage the plates 51. The nut is then rotated in the opposite hand direction to retract the impellers and to thereby restore the original clearances 52 between the wearing plates.

The arc through which the nut must be rotated to establish such clearance may be readily determined from the lead of the threads of the portion 6% of the impeller shaft. In thus rotating the nut 61 it is, of course, essential to again bring its bolt holes into alignment with those of the coupling members for re-insertion of the bolts 67 but, owing to the close spacing of the holes the nut need be rotated only slightly in one direction or the other from any given position to establish such registry and the widths of the clearances 52 will be little affected by such maneuvering of the nut.

As will be readily apparent from the foregoing description, these adjustments of the impellers axially of the impeller chambers may be conveniently made without requiring the dismantling of any of the essential parts of the pump assembly and without disturbing its bearing portions or the devices serving to seal the pumping chambers from the bearing portions.

We claim:

1. In an adjusting device, the combination of a centrifugal pump casing having an impeller chamber, an it ipeller in the impeller chamber, an impeller shaft in the casing secured to the impeller, a drive shaft for driving the impeller shaft positioned in axial alignment therewith, a coupling comprising coupling members on the shafts for drivingly connecting said impeller shaft to the drive shaft and constituting the sole driving connection therebetween, one of said coupling members being slidably connected with the impeller shaft against rotary motion relative thereto, another coupling member on the drive shaft and secured against rotary motion relative thereto, adjustable means engaged to the impeller shaft against longitudinal movement relative thereto, means engaging the adjustable member and said coupling members for maintaining the coupling members in coaxial alignment and holding the adjustable member in an adjusted position, said adjustable means being movable longitudinally relative to the impeller shaft upon release by the last said means for effectin g endwise movement of the impeller shaft relative to the casing.

2. In an adjusting device, the combination of a centrifugal pump casing having an impeller chamber, an impeller in the chamber, there being a clearance between the eyeend of the impeller and an opposed surface of the cham her, a shaft for the impeller, a drive shaft for driving the impeller shaft positioned in axial alignment therewith, a coupling comprising coupling members for drivingly connecting the impeller shaft to the drive shaft and constituting the sole driving connection therebetween, one of said coupling members being slidably interlocked with the impeller shaft against rotary motion relative thereto,

another coupling member on the drive shaft and secured against rotary motion relative thereto, the end portion of the impeller shaft adjacent the drive shaft being threaded, a nut between the coupling members threadedly connected with the threaded portion of the impeller shaft for effecting endwise movement thereof to move the impeller relatively to such opposed surface of the chamber, and bolts for clamping the coupling members to the nut interlockingly engaging the nut to prevent unauthorized rotative movement of said nut with respect to the impeller shaft.

3. In an adjusting device, the combination of a centrifugal pump casing having an impeller chamber, an impeller in the chamber, a hollow shaft in the casing, an impeller shaft secured to the impeller and having a sliding lit in the hollow shaft, a drive shaft for driving the impelleshaft and positioned in axial alignment therewith, a coupling comprising coupling members for drivingly con necting the impeller shaft to the drive shaft and constituting the sole driving connection therebctween, one of said coupling members being fixedly secured to the hollow shaft and being slidably interlocked with the impeller shaft against rotation relative thereto, another coupling member on the drive shaft: and secured against rotary motion relative thereto, the end portion of the impeller shaft adjacent the drive shaft being t readed, a nut between the coupling members threaded on the threaded portion of the impeller shaft for imparting endwise movement thereto to move the impeller axially of the impeller chamber, and means for securing the coupling members and the nut togetherv 4. A device for adjusting and maintaining a pump shaft relative to its casing which comprises a sleeve surrounding the shaft and keyed thereto, a thrust bearing mounted on the sleeve and fixed axially with respect to such casing, a threaded member on said shaft to permit movement of said shaft axially with respect to said sleeve, means to couple said threaded member with the sleeve axially and radially including a pair of shaft coupling members, one of said members being attached to said sleeve, and coupling bolts holding said members rigidly together with said threaded member there between.

5. An adjusting device for adjusting the longitudinal position of a longitudinal movable'shaft relative to a longitudinal stationary shaft positioned in axial alignment therewith, a coupling connecting the shafts for transmitting rotary motion therebetwcen and constituting the sole driving connection therebetween, said coupling comprising a coupling member on the end portion of the movable shaft adjacent the stationary shaft and slidably connected against rotary motion relative to the movable shaft, a coupling member on the stationary shaft end portion adjacent the movable shaft and secured against rotary motion relative to the stationary shaft, adjusting means between the coupling members adjustably connected with said end portion of the movable shaft for effecting longitudinal adjustment thereof relative to the stationary shaft, and means for securing said coupling members against movement relative to each other and for holding the adjusting means in its adjusted position.

6. An adjusting device for adjusting the longitudinal position of a longitudinal movable shaft relative to a longitudinal stationary shaft positioned in axial align ment therewith, a coupling connecting the shafts for transmitting rotary motion therebetween and constituting the sole driving connection therebetwcen, said coupling comprising a coupling member on the end portion of the movable shaft adjacent the stationary shaft and slidably connected against rotary motion relative to the movable shaft, a coupling member on the stationary shaft end portion adjacent the movable shaft and secured against rotary motion relative thereto, the end portion of the movable shaft adjacent the stationary shaft being threaded, and means between the coupling members threadedly connected with the threaded portion of the movable shaft for effecting longitudinal adjustment thereof relative to the stationary shaft and having a portion adapted to be clamped between said coupling members to hold said means in its adjusted position.

References Cited in the file of this patent UNITED STATES PATENTS 1,519,391 Benson ..'Dec. 16, 1924 6 Roco et a1. Ian. 13, 1925 Adams June 22, 1934 McHugh Feb. 19, 1935 Greene Nov. 10, 1953 FOREIGN PATENTS Germany Aug. 25, 1952 

